If you send a chat to anyone else with the app you’ll use your inclusive data allowance, or it’s free over Wi-Fi. (You can track your data usage in the My Vodafone app.) Standard charges apply for messages sent as a text or picture message.
To use Message+, your device must be running iOS 6.0 or later, or Android 2.3 or later.
How do I enable contacts?
Enable the Message+ app to access your device‘s contacts when you install it. If you initially denied the app access, you can enable it by going to Settings > Privacy > Contacts and switching Message+ to ‘On’.